如何获得在轨道3所有数据库行的范围有多大？ [英] How to get a scope for all database rows in rails 3?

问题描述

假设我们以下设置：

class Post < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :posts
end

进一步假设用户有一个布尔属性管理员，这表明，如果他是一个全球性的管理或没有。

assume further the user has a boolean attribute 'admin', which indicates if he is a global admin or not.

我想写一个为用户类，称为visible_posts的方法（或范围有多大？）。如果用户是没有管理，它应该只返回自己的岗位。如果他是admin的方法应该返回所有文章在系统中。

I want to write a method (or a scope?) for the User class, called 'visible_posts'. If the user is no admin, it should return just its own posts. If he IS admin the method should return all posts in the system.

我的第一次尝试是这样的：

My first attempt was something like this:

class User < ActiveRecord::Base

  [...]

  def visible_posts
    if admin?
      Post.all
    else 
      posts
    end
  end

end

这里的问题是，Post.all返回一个数组，但我宁愿希望有一个ActiveRecord ::关系就像我的帖子后获得与它的工作。

Problem here is that Post.all returns an Array, but I would rather like to have an ActiveRecord::Relation like I get from posts to work with it later on.

是它在某种程度上可能得到一个ActiveRecord ::关系的重新presents的所有帖子？

Is it somehow possible to get an ActiveRecord::Relation that represents ALL posts ?

推荐答案

您可以做 Post.scoped 我想用Rails

You can do Post.scoped i guess in Rails

和后面这一点，你可以调用。所有来获取结果

And later on this you can call .all to fetch the results

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